The present invention relates generally to the field of high pressure processing of materials. More particularly, this invention relates to a method for the compaction and consolidation of discrete powder particles using application of high pressure in combination, as appropriate, with application of high temperatures for short periods of time, and, further relates to novel articles of manufacture produced thereby.
Previous methods for the shock processing of solid materials including discrete powder particles utilized high explosive materials in contact with the article, or high explosive materials utilized to accelerate a plate which strikes the article imparting pressure shock thereto. However these methods are cumbersome and not always reproducible.
In addition, it is difficult to shock process non-planar surfaces and complicated geometries and the processes are difficult to automate and fail to meet some industrial needs, particularly in a process known as "hot isostatic pressing" or "HIP" which is commonly used to compress powders into a fully dense, solid part or article.
Conventional HIP is commonly characterized as a "creep" process. Pressure is applied to force into tight union the various surfaces to be bonded. Heat is applied to increase the molecular motion of the proximate surfaces, leading to diffusion of one surface into another. This mass diffusion resulting from molecular interpenetration of surfaces held together by pressure leads to fully dense, chemically bonded materials typical of HIP processing. However, conventional HIP processing requires hours at elevated temperature and pressure for adequate mass diffusion and densification to occur; that is, for the surfaces to "creep" together.
The present invention describes a method in which pulsed lasers are used to densify powder or particulate materials for subsequent processing such as in HIP processing.